"I had a very definite idea at the back of them," Dennis replied. "I thought perhaps the white chalk which was deposited in the blade-pocket, and was even noticeable on the handle, might be due to billiard chalk. But, of course, I didn't mention billiards, because it would have given my line of reasoning away. I thought it was better to spring it on them with a bump." "Which you certainly did," I laughed. "As a matter of fact, I thought you were simply having a game with us all. But now that you've told me the details, Den, do you remember what happened when you did spring it on them?" "Well, of course I do," he replied. "But even so, I hardly know what to make of it. I should like to feel confidently that Fuller is the man we are after. But we must remember that both he and Hilderman might very easily have thought I really had discovered something from the knife and been exceedingly surprised without having any guilty connection with the discovery." "H'm," I muttered, "I prefer to suspect Fuller." "Oh, I do too," Dennis agreed. "It is safer to suspect everybody in a case like this. But why are you so emphatic?" "Well," I explained, "we have a few little things to go on. Myra diagnosed that Sholto was taken on a yacht by Garnesk's left-handed man in sea-boots. Then you produce a left-handed member of a yacht's crew out of an old pocket-knife, and Fuller jumps out of his skin when you mention it. That seems to be something to go on, and then there was that incident in the smoking-room." "When you were reading the paper?" he asked. "I couldn't make that out. Did you notice anything suspicious about it?" "Of course I was in a suspicious mood," I admitted, "but it struck me as a singularly rude thing to do to snatch the paper out of my hand like that. His remark about Hilderman's precious view was very weak. I think there was something behind it." "What?" asked Dennis. "It may have been that there was a letter, or something in the way of a paper, which he didn't want me to see laid inside the paper; but there was another curious point about it. There was a page torn out. I had just noticed this and was on the point of making some silly remark about it when Fuller leaned right across you and took the thing from me, as you saw." "If the page he didn't want you to see was torn out, there was no chance of your seeing it," Dennis argued, logically enough. "No," I agreed, "but after your exhibition, if he had anything to conceal he may have been afraid of my even seeing that the page was torn out." "What do you imagine the missing page can possibly have contained?"